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' IMPOVEMENT IN FLOOR-GLAMPS.

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'ro ALL WHoM 1T MAY CONCERN: y I n Be it known that I, HENRY D. BARNES, ofFair Haven, in the county oi'iNrcw Haven, and State ofConvnecticut, have-invented a new Improvement in Screw-Clamp; and I do hereby declare; the following, when taken inl-connection with the accompanying drawings, and the letters of reference markedthereon, to be a full,"clear, and exact description of the same, and which Vsaid drawings constitute-partei' this specification,

Figure 1, a side view,

Figure 2 a. top view, and in Figure 3 a partial central section. K p This vinvention relates to an improvement-in clamps, such as are used by wood-workers and others for clamping their Work, and consists in the 4peculiar construction whereby the long screw usuallyhemployed is .reduced in length, and the operation of the clamp very much facilitated.

To enable others to construct my improvement, I will proceed to describe the same as illustrated inlthel accompanying drawings.

VA is the beam, and B the jaw formed upon or fixed thereto. I prefer to make the beam `A of T-shape,` as l denoted in'g. 2.

. Heretofore the screw has been inserted through a fixed bar or jew at the other extreme of `the beam, so

-that it is necessary to run the screw from end to end, according to the thickness ofthe material to be clamped.

. To avoid this necessity I arrange an arm, C, upon and so as to move up and down on the beam A, from` on`e extreme `to the other, and in the end of the said arm I x a. nut, D, through which a. short lscrew, E, is.,` passed, and I secure the saidarm C upon the beam A by formingthe edge of the beam serrated, or with teeth, fas Adenoted in figs. 1 and 3, and `within that portion F of the arm C whichV surrounds the beam .AI` arranged plate, a, (see g. 3,) provided with corresponding serrations, and on to the said plate through u nut, G, in the,` i :1r-mp1 insert 'a set-screw, Hfwhich, bearing. down on to the said plate, sets the plate intothe corresponding i serrationsonthe'beam, thus securely holding the arin C in any desired position on the beam, so that if `u` thini substance is to be clamped, the arm C may be set down accordingly, as denoted in black; or, if for thick, up, f

as `denoted in red; and thus necessitate but a short movement of thc screw.

I do not wish to be understood as broadly claiming a clamp-screw constructed with an adjustable arm, as.l

such are common and well known.

i Having thus fully described my invention, what I claim as new and useful, and desire to secureby Letters` 1 Patent, is-

The arrangement of the serrated plate a within the arm C, combined with a corresponding serrated surface of `thebeam A and the set-screw H, constructed and arranged so as to secure them-m G upon the beam A, substantially in the manner herein set forth.

HENRY D. BARNES. Y

Witnesses: i

A. J. Tnsrrs, JoHNiH. SnUMwuY. 

